Microbial Enhanced Oil Recovery Microbial Process Technology Elda Renedo Gil Abdelrahman Abdelkader Ihab Hashem Jesse Verlinden

Overview Introduction Technology Economical, ecological and social assessment Conclusion Highlights

Introduction Oil extraction from well Primary recovery: natural mechanisms (5-10%) Natural gas expansion Secondary recovery: fluïd injection (25-30%) Water or natural gas circa 65% not recovered Let us have a look which methods are available for oil extraction from a well. The first methods applied to extract oil from a new oil field are part of the primary recovery. They use natural mechanisms for oil extraction, which means that the underground pressure is sufficient to force the oil to the surface. The major natural mechanism is the expansion of the natural gas present in an oil field. As pressure decrease due to depletion, dissolved gas in the oil evaporates and raise the pressure, and so supplying new driving forces. Also some minor effects result from water expansion and gravity drainage. In the primary recovery step, only 5-10% of the oil present in an oil field can be recovered. After this first step, secondary recovery is necessary to extract more oil from the oil field. They rely on the supply of external energy into the reservoir in the form of injecting fluids to increase reservoir pressure, hence replacing or increasing the natural reservoir drive with an artificial drive. Water and natural gas are injected to increase the pressure in the oil field. Secondary recovery is able to extract an additional 25-30% of oil. After Secondary recovery, still 65% of the oil is not recovered!

Introduction Primary recovery: natural mechanisms (5-10%) Secondary recovery: fluïd injection (25-30%) Tertiary or enhanced oil recovery (EOR): Gas injection Thermal recovery (TEOR) Chemical injection Alkaline, surfactant, polymer and MICRO-ORGANISMS MEOR Extra 20-30% recovery! That is why tertiary or enhanced oil recovery technologies are necessary, knowing that oil fields are rare and fossil fuel is our major energy source. 3 major techniques are available. With gas injection, carbon dioxide, natural gas or nitrogen gas is injected, with the purpose of reducing the interfacial tension between oil and water, and to reduce the viscosity of the oil, to facilitate flow. With thermal injection, heat is supplied to reduce the viscosity and partly vaporize the oil. The heat is mostly supplied by steam injection. Lastly, injection of several mostly diluted chemicals is used to reduce surface tension and viscosity. Alkaline and polymer solutions, surfactants but also micro-organisms are injected. The injection of micro organisms is used in microbial enhanced oil recovery and we will discuss this technology during this presentation. The enhance oil recovery methods recover an additional 20-30% of oil. We will focus on the enhanced oil recovery by chemical injection of micro-organisms.

Technology

Technology Nature of microorganisms halophile, barophile, thermophile microbial strains Source of microorganisms Two major ways: Selective plugging Metabolites production Hydrocarbon-utilizing & non-pathogenic Halophile = salinity One of the challenges is to isolate these strains Mostly naturally occurring in the reservoir & genetically engineered Need nutrients mainly molasses  cheap

A. Selective plugging Microorganisms plug the higher permeable path to get the oil from other places Water with nutrients and microorganism or already exist http://www.titanoilrecovery.com/titanprocess1.html

A. Selective plugging adapted from http://www.titanoilrecovery.com/titanprocess1.html

B. Metabolites production Gases, solvents and acids Re-pressurizing Reduce oil viscosity Carbonate rock dissolution Gases: CH4 CO2 H2 Acids: Acetic

B. Metabolites production Biopolymers and biofilms Plugging effect: dead bacteria vs. polysaccharides More efficient than the bacteria bodies Metabolites adhesion force

B. Metabolites production Biosurfactants Interfacial tension Wettability Surfactants do what surfactants do!

B. Metabolites production Biosurfactants Interfacial tension Wettability

Economical, ecological and social assessment.

Economical feasibility Increase in the production of oil Higher economic lifetime of the wells. Reduction in water cut achieved Low operating cost Minor modifications to existing field facilities. Profitable and economically feasible MEOR PROCESSES WILL LEAD TO AN INCREASE IN THE PRODUCTION OF OIL. Some fields trials reported an increase of 45.6%. Therefore incrising the lifetime of a well. A significant reduction in water cut was observed (% of water in the oil flow throught pipes) It is a low cost process: does not consume large amounts of energy and it does not depend on the oil price It can be implemented easily with minor modifications to existing field facilities. It has proven to be profitable and economically feasible

Economical feasibility Drawbacks: Need of a better understanding of the MEOR processes Scaling up Not enough field applications However , there is a need of a better understanding of the MEOR processes and mechanisms behind them, from an engineering point of view. A Better knowledge of then economics, applicability and performance is the key to further improve the process efficiency. It is as well difficult to scale up, and to translate the laboratory results to real-time oil field setups. Because of the these reasons there aren’t enough fields trials or applications yet.

Ecological impact Safe to handle and pose no threat Eco-friendly Toxicity test; Long term effects Lack of understanding of the mechanism Difficult to extrapolate results Studies reported MEOR processes as safe to handle and pose no threat to the environment, plants, animals or human beings (these is based on tests conducted by public health laboratories) It is an environmentally friendly petroleum recovery process Still it is compulsory to perform a toxicity test for any organism to be used in the field for MEOR to assure the safety of involved parties. And the main concern are the long term effects, which are not well known, due to inconsistent technical performance( haven’t being running for long enough time) and lack of understanding of the mechanism of oil recovery Another aspect is the Difficulty of extrapolating the results from one microbial field trial to other reservoirs as each reservoir has its unique properties and microbial population for indigenous MEOR cases

Sociological impact of the process Environmental concerns Insufficient knowledge of the process mechanism Consequences of pumping bacteria to ground

Source: survey by the university of Lethbridge, Alberta, Canada

Source: survey by the university of Lethbridge, Alberta, Canada

Conclusion

Conclusion Need for tertairy oil recovery methods MEOR is promising technology on both the economical and environmental front But more research is needed... There is an economic need for tertiary oil recovery methods. Using MEOR results in a signifigant increase in oil production and higher economic life of the well. MEOR has a minimal ecological impact and poses no threat to the environment. Long term effects! Need for more studies to understand the mechanisms of oil recovery and scaling up. Need for communicating the results to society.

Highlights

Highlights Traditional oil recovery methods can only produce 35% of the well capacity Tertiary oil recovery can get an additional 20-30% MEOR is a technology that manipulates microbial environment in an oil reservoir in order to improve the oil recovery from porous media. Microorganisms used should be hydrocarbon-utilizing and non-pathogenic. Microorganisms used are a mixture of naturally occurring in the well and genetically engineered microorganisms.

Highlights Oil recovery occurs through two main mechanisms: selective plugging and via metabolite production. In selective plugging, microorganisms plug the higher permeable paths forcing water to residual oil paths. Metabolites produced by bacterial action can lead to a reduction in oil viscosity and carbonate rock dissolution. The process has low operating costs and can be implemented in current plants. Economically feasible and pose no threats to environment, however not enough field applications.

Thank you

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